1. Field
The invention is in the field of weather and/or traffic resistant joints between adjoining structural slab materials, especially in concrete highways, and of methods of making same.
2. State of the Art
Many different ways of making joints of the type concerned have been proposed heretofore to overcome the various problems associated with interconnecting adjoining slab materials. Of special concern has been the providing of both weather and traffic resistant expansion joints in concrete highways.
It has become common practice to cut expansion joint channels transversely and/or longitudinally in a concrete highway above the usual shrinkage control cuts or construction joints by the use of diamond saws, and to introduce a more or less hard-setting but ductile and elastic silicone adhesive into such channel cuts as a joint filler above a semi-rigid backer bar insert. As a weather proofing agent, the adhesive will adhere to the opposed concrete facings of such cuts and after curing into final hardness will tend to move with the expanding and contracting adjoining concrete slabs. It is usual to clean the channel cuts by flushing with water followed by high pressure water blast or sand blast prior to introducing the silicone adhesive. Although certain silicone formulations designated for highway use are presently available commercially from several manufacturers on the basis of long-range testing showing several years of generally trouble-free performance under heavy traffic conditions, the reduction of costs associated with the construction and replacement of such joints, together with improvements in performance, have been the subject of considerable research activity by government highway departments and by supplies of materials thereto considering the tremendous number of such joints necessitated by the many miles of concrete highway in most countries of the world. Other types of field-cured elastomeric materials as well as preformed and precompressed lengths of various elastomer materials have been introduced into joint installation channels for sealing purposes with only indifferent success.